Cut your fabric across the diagonal. Then with right sides together sew the short edges together. Repeat for the fleece.
Open up and put two fabrics right sides together. Sew around all the edges leaving a small hold to turn the pieces right side out.
Turn right sides out and iron. Iron the edges at the hole under and sew closed.
On one end add a 1 inch button hole.
Thread the other end through the button hole and you’re good to go!